Flight Sim Motion
1300W Yard Tractor
Ball & Sockets Joints
Chains & Sprockets
Motion Platform 2
Low-cost DIY Linear Actuator
DIY 3 DOF Flight Simulator Motion
Simple Vehicle Power
Calculator using Imperial Units
You decide if laden, partially laden or
unladen weight is used - the more heavily loaded the vehicle is
the bigger the power consumption. Speed is that at which vehicle power is to be
calculated, note that the faster the vehicle goes the more power
it needs. HINT - if you are towing another wheeled
vehicle/trailer/implement adding its weight here will bring it
into the calculation (underlying assumption is that the Rolling
Resistance specified below applies to both vehicle and trailer).
Coefficient of rolling resistance, Cr
Rolling resistance is dependent on ground
conditions and tyre/wheel design. Click
here for help and
suggestions on what value to use. The calculator assumes a
single Cr for the vehicle (ie all wheels/tracks have the same
Cr). Normally the Cr figure relates only to the natural
resistance of a wheel to roll - ie issues such as bearing
friction are not included. If you are likely not to use low
friction bearings you might increase Cr to compensate.
Alternatively specify a drive transmission efficiency below.
Angle of climb, 1 in
Hill climbing can be a big contributor
to required power - specify gradient in the form "1 in 10", "1 in 50", etc -
anything flatter than 1:1000 will be taken by the calculator as on-the-level.
Drag Coefficient, Cd
Vehicle Frontal Projected Area,
Representative frontal width
Representative frontal height
Drag is strongly speed dependent and is felt
much more at higher speeds than low. If you have a slow moving
vehicle this component of drive force might be well be ignored.
Drag coefficient is dependent on vehicle
Click here for help and suggestions.
Either input the frontal projected area directly or
specify the width and height of the vehicle (the area will then
be approximated at 0.9 x W x H).
A value is suggested for air density at
normal atmospheric pressure.
NOTE - This is an input to the power calculation, not an
output. It allows the calculator to determine the power required
to achieve the specified acceleration - you state the required
Change in speed
Time taken to achieve this speed change
The calculator can work out
the acceleration figure it needs if you tell it by how much vehicle speed changes
over what period of time. For example 0 to 60 mph in 10 seconds
can be specified as a 60 mph speed change in 10 seconds, or a 6
mph change in 1 second. 40 mph to 60 mph in 2 seconds can be specified as a 20
change in 2 seconds. The calculator assumes that this magnitude
of acceleration is present at the vehicle speed specified at the
top of the page.
Any Additional External Force
This allows you to add in extra effects such as
towing or pushing. If you have a tow bar pull you want to
accommodate then you can add it in here.
Mechanical Transmission Efficiency
The calculated power is the ideal mechanical
power required at the wheels to drive the vehicle under the
conditions you describe. The motor output power will need to be
more than this - because some is lost in the
mechanical transmission. If you specify a transmission
efficiency (in %) a figure for motor output power will also be
A new window will open with a summary of your
input data and the calculation results. Use the browser's "Back"
button return to this page to run a repeat calculation with different
input data. This way you can build up a picture of how the
results vary with design and/or operating condition changes.
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